Splicing Factor HnRNPA2B1 Contributes To The Tumorigenic Potential Of Breast Cancer Cells Through The STAT3 And ERK1/2 Signaling Pathway

Part 1.Splicing factor hn RNPA2B1 contributes to the tumorigenic potential of breast cancer cells through the STAT3 and ERK1/2 signaling pathwayBackground: Increasing evidence has indicated that the splicing factor hn RNPA2B1 plays a direct role in cancer development,progression,gene expression,and signal transduction.Previous studies have shown that knocking down hn RNPA2B1 in breast cancer cells induces apoptosis,but the mechanism and other functions of hn RNPA2B1 in breast cancer are unknown.The goal of this study was to investigate the biological function,clinical significance and mechanism of hn RNPA2B1 in breast cancer.Methods:The expression of hn RNPA2B1 in 92 breast cancer and adjacent healthy tissue pairs was analyzed by immunohistochemical staining.Stable clones exhibiting knockdown of hn RNPA2B1 via sh RNA expression were generated using RNA interference technology in breast cancer cell lines.The effects of hn RNPA2B1 on cell proliferation were examined by MTT and EDU assay,and cellular apoptosis and the cell cycle were examined by flow cytometry.A nude mouse xenograft model was used to elucidate the function of hn RNPA2B1 in tumorigenesis in vivo.The role of hn RNPA2B1 in signaling pathways was investigated in vitro.Res?lts: Our data revealed that hn RNPA2B1 was overexpressed in breast cancer tissue specimens and cell lines.Knockdown of hn RNPA2B1 reduced breast cancer cell proliferation,induced apoptosis,and prolonged the S phase of the cell cycle in vitro.In addition,hn RNPA2B1 knockdownsuppressed subcutaneous tumorigenicity in vivo.On a molec?lar level,hn RNPA2B1 knockdown decreased STAT3 and ERK1/2 phosphorylation.Conclusions: hn RNPA2B1 promotes the tumorigenic potential of breast cancer cells through the ERK1/2/ STAT3 pathway,which may serve as a target for future therapies.PART.2 IL-21 effects mechanism of trastuzumab resistancein HER2 positive breast cancer cell linesBackground: Trastuzumab treatment is the only targeted therapy for patients with HER2-positivebreast cancer.However,the patients show seriously drug resistance,which aredrawn more and more attention.To understand the resistance mechanisms then solvethe problems,and to enhance the efficacy of drugs has become key point oftreatment on HER2-positive breast cancer patients.According to this problem,thisresearch aims to observing the effect of IL-21 in trastuzumab treatment forbreast cancer.Methods:The study to verify the trastuzumab drug sensitivity in HER2 positive breast cancer cell lines by CCK-8 assay.Through the ELISA and flow cytometry technology,totestthe IFN-gamma and granzyme B that release from NK cells to indirect observe the role of IL-21 in trastuzumab treatment.Res?lts:Compared with UACC-732 and JIMT-1,the growth inhibition rate in SKBR3 and BT474 cell is lowafter treat with different concentration of trastuzumab.In other word,the drug trastuzumab sensitivity is higher in SKBR3 and BT474 cell lines.In JIMT-1 cells,the concentration of IFN-gamma which realease from NK cell is higher after treat with IL-21,compare with control group.And the higher level of granzyme B was observed in IL-21 and NK cell co-incubation groups in UACC-732,JIMT-1 and SKBR3 breast cancer cell linescompare with control groups.Conclusions:UACC-732 and JIMT-1 are innate resistance cell line of trastuzumab compare with sensitive cell lines SKBR3 and BT474.IL-21 can effectively improve NK cells to release cytokines,and theninduce ADCC effect.